MTD MechanicsW.J. Llope
MTD ReviewBNL, Sept. 17, 2010
Outline:
• MTD7 & MTD9 Prototypes
• MTD11 ProjectNew MRPC designFirst Bench/Cosmics Results
• Full SystemTray DesignTray MountingMechanical IntegrationGas & HV systemsAssembly Team & Space
• Conclusions
MTD7Two “LMRPCs” end-to-end
2x6 strips
TOF-style “shoebox” enclosureBuilt in HoustonAssembly at BNL
Simple FEE & long cablesDigitization on platform
in old TRG electronics (CDB boards)
Operated throughout Runs 7 and 8...
Showed “matching enhancement”from muons
Smooth operation, no major problems...
Time resolution was poor (~300ps)due to long cables and digitizers used.
2
MTD9Three “LMRPCs” side-by-side
3x6 double-ended strips
Very heavy “Shoebox” enclosure
TOF TINO FEETDIG on-board digitization
Operated throughout Runs 9 and 10...
wide unistrut frame w/out detector.... frame with MTD9 installed....
3
Three “MTD11” trayson one backleg @ 12 o’clock
Existing MTD9 trayEast, ~10 o’clock
MTD11 PatchThree “WMRPCs” on one backleg
12 double-ended strips in each boxPlus MTD9 tray
All with MFTB/MINO/MTRG electronics
MTD11 MRPCs (3 needed) from:USTC (2 MRPCs)Tsinghua (1 MRPC)
Main Goals of this effort are:
design & implement new tray structure for WMRPCs, & tray mounting scheme
develop installation and maintenance procedures (including BEMC!), gain operations experience
show successful operation of WMRPCs in STAR in Run-114
strip length/inner glass: 870
graphite layer: 880
outer glass: 890
Mylar: 895
PCB: 915st
rip
wid
th:
38
gap
: 6
effe
ctiv
e w
idth
: 5
22
inn
er g
lass
/gra
ph
ite:
54
9
ou
ter
gla
ss:
55
9
My
lar:
56
4
PC
B:
58
0
USTC PrototypeOuter (PCB) 58.0cm x 91.5cmActive (Pads) 52.2cm x 87.0cm Height = 3cm Weight = 13kg (29lbs)
5
USTC also intends to build a 220µm version
USTC Prototype Dimensions
note these are single-stack MRPCs, unlike the “LMRPCs” used in MTD7 and MTD9
6
USTC Prototype -- First Bench Test Results
Position 1 straddles two strips, Position 2 is centered on a single strip
Noise Rates: (note 330 Hz = 1 Hz/cm2)
7
First Tsinghua Prototype
slightly longer (93cm instead of 91.5cm)
8
Tsinghua Prototype -- First Bench Test Results
Using 95% Freon + 5% isobutane
Statistics limited still, will continueto test 2-3 more weeks
Efficiency >90% at 6.9 kVTime Resn <75ps
noise rates at 7 kV are ~0.3 Hz/cm2
good uniformity
9
MTD11 and Full System “Tray” Basic Idea
Minimize box w.r.t. WMRPC (minimize gas volume, weight, footprint)
Welded architectural aluminum channel + bottom plate (UT-Austin)
Precision 90mil top plate w/ PEM studs (Oaks, Houston)
Tray Assembly&Test at UT-Austin
Top welded to sidesBottom bolted & DC730 sealed
All trays have3-layer stack of MFTB MINO TDIG
1 TCPU & 1 MTRGper backleg,on “center” tray
lower layer of trays bolt to Unistrut(through holes in the short channels)
upper layer of trays bolt to lower layer(through holes in the long channels)
10
HV & Gas F/Ts on long sidesno internal gas tubingdelrin spacers in 3D to hold WMRPC w.r.t. tray box
11
All Trays are mechanically:
exactly the same
perfectly symmetric (can be rotated 180 in-plane if necessary)
i.e. each tray can be installed “anywhere”
A “center” tray (installed at Z=0) has 5 boards (MFTB, MINO, TDIG, MTRG, and TCPU)...
Other trays on the same backleg do not have MTRG or TCPU
Gas In
HVneg
HVpos
Gas Out
12
Parallel Design Effort (Llope & John Scheblein)
13
Full System Tray Placement
mutdgeo.gconfig=5
http://wjllope.rice.edu/~MTD/MTDintegration.pdf
14
3-Tray Backleg Layout
Unistrut channel bolts to BEMC box.Lower row of MTD trays bolts to unistrutUpper row bolts to lower row.
Center Tray “high”MTRG and TCPU boards on center tray
Upper tray to lower tray bolt Lower tray to unistrut bolt
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5-Tray Backleg Layout (draft - still making small changes to tray length etc)
Unistrut channel bolts to BEMC box.Lower row of MTD trays bolts to unistrutUpper row bolts to lower row.
Center Tray “low”MTRG and TCPU boards on center tray
“foot space” at end of BEMC boxes
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Two general integration issues..
1. Access to MTD trays and BEMC Boxes underneath:
2. Mounting to Boxes “underneath” STAR...
BEMC PMT Box Bridge Interior of BEMC PMT Box
Bridge does roll East/West
Discussions are continuing
present idea is to build a support “bed”
and
modify hanger brackets
17
Gas System
Proposal: MTD trays are “additional” TOF traysNow: Separate MTD system
Clean triggering is crucial for this systemWill push to include 0.5% SF6 in the gas mixtureCannot do this in a gas path that includes TOF trays
MTD gas system proposed to operate in purge mode- simple system to build and operate
build-up of impurities in the gasincreased noise rates
might etch glass over long terms
should not join TOF & MTD gas systems!
HV SystemPerfect copy of TOF’s approach - simply an expansion of this system
All components are already BNL safety-approvedSpace for 2x2 additional supply cards exists in TOF mainframe...Spare mainframe already in handControls and monitoring interface already in place, simple extended for more channels
Same TOF-style “Long cables” from supply to distribution boxes...Ten TOF-style HV distribution boxes (5 east and 5 west)...Same TOF-style “Short cables” from distribution boxes...
18
Tray Assembly and Test at UTexperienced team, proven expertise with MRPC assembly and full-tray testingexisting assembly space with all of the necessary tables and toolslarge machine shop with many craftsmen
large assembly room with custom tables tables with TOF trays
full tray test stand storage racks and tray leak testing
19
Summary
Successful design and integration of MTD7 and MTD9 detectors in STARsame design and integration team involved for the full system
MTD11 project is funded and on track to install 3 full-size prototypes before Run 11Verify successful operation of these MRPCs in STARCommission triggering interfaces and implement MTD triggersDevelop fixtures and gain experience installing/removing the detectors
Design of final system trays will be very similar to that for the MTD11 traysFinalize design of full system trays by March 2011
HV system is simply an extension of the existing TOF systemSystem is well known to the shift crews, simple turn-key operation
Gas system is much simpler than TOF’sPurge mode (no recirculation)Some components are already in place
Experienced and expert assembly team in place at UTFloor space, tooling, fixtures, and excellent machine shop already in place
Detectors and final electronics tested as complete units in TexasDelivered to BNL, and quickly retested before installation in STAR
